DE1282078B - Cryotron gate circuit - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY DEUTSCHES ^ STYKnS PATENTAMT Int. Cl .:

H03k

EDITORIAL

German class: 21 al -36/18

Number:
File number:
Registration date:
Display day:

P 12 82 078.9-31 (J 24817)

November 28, 1963

November 7, 1968

The invention relates to a cryotron gate circuit, in which consisting of superconducting layers, Gate ladder, control ladder and shielding ladder arranged one above the other run parallel to one another, wherein between a control conductor and a shielding conductor a gate conductor with a soft superconducting material existing section is provided.

In such a cryotrontor circuit, known as a parallel cryotron, a current in the control ladder due to the resulting magnetic field of the gate ladder from its superconducting in its normally conducting state can be switched. Parallel cryotrons show in relation to such Layered cryotrons in which the control ladder and the gate ladder run at right angles to each other, has a relatively high resistance without using extremely thin gate conductors have to. Furthermore, by using control and gate ladders of the same width, during operation of the control conductor with a certain bias voltage or by using a separately arranged Pre-excitation conductor a gain of more than 1 can be achieved.

In the case of a parallel cryotron that has already been proposed, a construction with only one superconducting Shielding plate used. However, parallel cryotrons are stacked on top of one another to save space as much as possible It is to be able to stack without undesired coupling between the cryotrons desirable to have a shield on the other side of the parallel cryotron as well. Such Parallel cryotrons have not yet become known; on the contrary, it has hitherto been of the opinion that with a parallel cryotron with shields on both sides no current gain can be achieved could.

The present invention is therefore based on the object of creating a cryotront gate circuit, In which shields are provided on both sides and a current gain of greater than 1 can be reached.

A cryotrontor circuit according to the invention is characterized in that on the one of the former Shielding conductor arranged opposite outer side of the cryotron, a second shielding conductor and that the one arranged between the control conductor and the first-mentioned shielding conductor Goal ladder to one of these ladder has a relatively low cost.

In this space there is a relatively small distance due to the flow through the gate ladder Cryotron gate circuit

Applicant:

International Business Machines Corporation,

Armonk, N.Y. (V.St.A.)

Representative:

Dr. phil. GB Hagen, patent attorney,
8000 Munich 71, Franz-Hals-Str. 21

Named as inventor:
John Jacob Lentz,
Chappaqua, NY (V. St. A.)

Claimed priority:
V. St. v. America November 29, 1962
(241 005)

The current has a much greater magnetic flux density in relation to the other areas of the cryotron.

A particular embodiment of the invention is characterized in that the distance between the control conductor and the shielding conductor adjacent to it is greater than the distance between the gate conductor and the shielding conductor adjacent to it and that an anti-parallel mode of operation of the control ladder and the gate ladder is provided. The current gain that can be achieved in this embodiment is approximated by the ratio of the first-mentioned distance to the second-mentioned Given distance.

Another embodiment of the invention is characterized in that the control conductor and the gate ladder are provided for an anti-parallel mode of operation that between the control ladder and the second shielding conductor a further gate conductor is provided, whose current to the current in the first Gate ladder is opposite in the same way, and that the first gate ladder to the shielding ladder adjacent to it has a smaller distance than to the control conductor. In this embodiment is achievable for Current gain the ratio of the distances of the first gate conductor to the control conductor and to the adjacent shielding conductor is decisive. The arrangement of the additional gate conductor makes the inductive Coupling between the control ladder on the one hand and the gate ladders on the other hand

809 630/962

lifted so that significantly higher switching speeds see two superconducting shielding conductors 16 and 18 can be achieved. arranged. The individual leaders are from each other

Another embodiment of the invention by means of suitable, not shown in the figures is characterized in that the gate conductor and the insulating layers are separated. The gate ladder part 12 ^ 4 be control ladder for a parallel mode of operation protrudes 5 from soft superconducting material, z. B. Tin can be seen that between the control conductor and the or indium, while the remaining strip sections second shielding ladder, another gate ladder in front of gate ladder 12, control ladder 14 and the reticles whose current is to the current of the first goal screen conductor 16 and 18 made of hard superconducting male conductor is oppositely equal, and that the ab- terial, z. B. lead, are made. At the two distance between the control conductor and the first Torio shield conductors 16 and 18 exist at least their conductor is smaller than the distance between the first inner surfaces of hard superconducting material. Gate conductor and the shielding adjacent to this When operating a gate circuit according to FIG. 1 is

ladder. A current gain that is greater than 1, the gate conductor part 12 A superconducting. Current signals im is achieved by the fact that the first gate conductor closer control conductors 14 are then not present. If signals are fed to the control conductor 14 towards the control conductor as to the 15 adjacent to it, they generate shielding conductors. In this embodiment, a magnetic field of sufficient intensity to switch the control conductor asymmetrically superconducting gate conductor part 12 A into a normal, malconducting state between the two gate conductors. The then in and more towards the first gatekeeper; this allows gate conductor 12 caused resistance creates an inductive coupling between the 20, for example, a display of the control conductor falling on it and the first gate conductor, which because of the voltage; However, it can also serve to favor the current flowing in the parallel mode of operation when the control gate conductor 12 is inserted into a parallel current and thus to divert the switching speed of the superconducting current path made that

gene, in which inductive couplings, as a rule, its width is much greater than its thickness. lead to a reduction in the switching speed. 10,000 angstroms (10 ~ ⁴ cm) or less. It will

Further features of the invention are detailed later in the Pa- that it claims included. it is preferable to make the thickness of the gate noticeably larger

Embodiments of the invention are shown in FIG. 30 as the current drawing applicable at operating temperature and are shown below. - to make the penetration depth of the superconducting material, described in more detail. It shows in such a construction with thin, flat

Fig. 1 shows the cross section through an execution gate and control ladders and intervening form of the gate circuit according to the invention, thin layers of insulating material results

Fig. La is a perspective view of the. Execution of practically the same mode of operation of the form of the invention according to FIG. 1, according to the gate circuit when the signals are sent to a

Ib shows the characteristic curve for the current values for the single control conductor 14 (see FIG. 1) or if they In the embodiment, superconductivity is achieved on two control conductors 14 arranged one above the other according to FIG. 1, and 20 (see FIG. 2). Such a one

F i g. 2 the cross section of a variant of the variant is shown in FIG. 2 shown. The one shown there leadership according to Fig. 1 with an additional. second control conductor20 is also called a pre-excitation-pre-excitation conductor, ~ named head. In assessing the still to

FIG. 3 is the cross section of a further illustrative characteristic curve shown in FIG. 1b Approximate form of the gate circuit according to the invention with note that the in this diagram aufeinem Control conductor, on the opposite 45 carried control conductor current either in a one-sided the two gate ladder are arranged, zigen existing control ladder 14 (Fig. 1) flow-

F i g. 4 shows the cross-section of a variant of the execution current or in several control conductors 14 and form according to fig. 3 with a control conductor, which can mean 20 (Fig. 2) total flowing current, Fig. Ib opposite to the current in the gate conductor, shows the transition or amplifier

Current leads, 50 characteristic 21 for a gate ladder part 12 ^ 4 of the

FIG. 4a shows a perspective view of the embodiment according to FIG. 1. In the ordinate direction according to FIG. 4, is the gate conductor current I _g and in the abscissa direction

4b shows the characteristic curve for the current values for the total control conductor current I _c . To achieve superconductivity in the embodiment points below the curve, the gate conductor part 12, 4 according to FIGS. 4, 55 is superconducting; for points above the curve is the

■■ F i g. 5 shows the cross section of a variant of the execution gate ladder part 12 ^ 4 normally conducting. The diagram of approximate shape according to Fig. 4, in which the various Fig. 1 b applies to a gate conductor current, which are arranged asymmetrically in a conductor, certain direction flows, for example, in

F i g. 6 shows the cross section of a variant of FIG. 1 is indicated by a plus sign. The guide according to Fig. 5 with an additional 60 current in the control conductor can either be in the same pre-excitation conductor. Direction (see. + I _c in Fig. 1 and Ib) or in the

The gate circuit shown in Fig. 1 flows in the opposite direction (cf. —I _c in Fig. 1 and a parallel cryotron consists of a strip Ib) as the gate conductor current. Depending on whether a shaped control ladder 14 and a strip-shaped control and gate ladder currents flow in the same or in gate ladder 12, which flow a gate ladder part 12/1 (cf. 65 opposite direction, the operating Fig. La) is included. The gate conductor 12 and the way in which the gate circuit is controlled in the following as parallel conductor 14 are referred to one above the other, parallel to one another or anti-parallel. From Fig. Ib it can be seen, and at a certain distance from one another, that the behavior of the gate circuit follows

Fig. 1 with the same direction of the control and gate conductor currents differs significantly from the behavior of the gate circuit with opposing control and gate conductor currents. The value I _gc in FIG. 1b represents the critical gate conductor current for a control conductor current I ₁ . = 0, the gate switching from the superconducting to the normal conducting state. The values + I _C1 . and - / _ff indicate the critical control conductor currents that must flow in the control conductor in order to make the gate circuit normally conductive with a gate conductor current I _{K = 0.} The curve 21 makes it clear that the critical value for the gate conductor current increases with the simultaneous presence of an opposite control conductor current, as is the case with the anti-parallel mode of operation of the gate circuit. If the control and gate conductor current flow in the same direction, the critical value for the gate conductor current decreases in a striking manner.

The diagram of FIG. 1b resembles the characteristic curves of known parallel cryotrons consisting of superconducting layers, in which, however, a second shielding conductor 16 was not present and could not be used without destroying the possibility for current amplification. It is very important for the present invention that a second shielding conductor 16 can still be added without destroying the current gain of the gate circuit. To achieve this, the distance S between the gate conductor 12 and the first shielding conductor 18 must be smaller than the distance T between the control conductor 14 and the second shielding conductor 16. It has been observed that the current gain that can be achieved with such a gate circuit is approximately equal to the ratio T: S is. If these distances are changed, one must reckon with decreasing values of the ratio T: S that the height of the characteristic curve 21 decreases and assumes a more symmetrical shape with respect to the origin of the coordinates. The in F i g. 1 b corresponds to a high value of the ratio T : S. In the space marked S between the gate conductor 12 and the shielding conductor 18 there is a high magnetic field strength due to the current flowing through the gate conductor 12, which also exists in the absence of a control current. This is known as a state of magnetic saturation. This does not mean, however, that the space below the gate conductor is filled with magnetically saturable material, but that the dimensions of the space in question in relation to the remaining space around the gate conductor are designed in such a way that a much greater magnetic flux density per unit cross-sectional area is present in it occurs.

The diagram of FIG. 1b explains the mode of operation of an embodiment of the gate circuit according to both FIG. 1 and FIG. 2. The description that follows relates to the arrangement according to FIG. 2 and assigns the characteristic curve in FIG. 1b a further meaning. A pre-excitation current flows continuously through the pre-excitation conductor 20; Control signals are applied to the control conductor 14 in order to control the conductivity state (superconductivity - normal conduction) of the gate conductor. In larger circuit arrangements, the gate conductor of a first gate circuit is connected in series with the control conductor of a second gate circuit. For such an operation it is necessary that the gate circuit has a certain gain, ie that the signal required to switch the gate conductor to the normal conduction state is smaller than the gate conductor current that is just permissible for the gate circuit to remain in the superconducting state. Referring to FIG. 2 becomes a negative, the value I ₂ in FIG. 1 b, the corresponding pre-excitation current is supplied to the pre-excitation conductor 20. (Is in

ίο F i g. 2 indicated by the dot symbol to the left of the pre-excitation conductor 20). At the same time, a positive one, corresponding to the value I ₁ in FIG. 1 b, the corresponding gate ladder current (see FIG. 2, the plus sign to the left of gate ladder 12) is fed to gate ladder 12. Under these prerequisites, the operating point α results in FIG. 1 b, which lies between the two inclined straight lines 22 and 24. The straight line 22 corresponds to the slope of the part of the characteristic curve 21 located on the far left in the drawing;

ao the straight line 24 forms an angle with the abscissa of 45 ° and thus has the slope 1. To achieve a gain, it is necessary that the slope the left part of curve 21, as represented by straight line 22, is greater than 1; further

As the working point α must lie to the left of the straight line 24 with the gradient 1 after the pre-excitation and gate conductor currents have been applied.

If one wishes to switch the gate conductor part 12Λ in the exemplary embodiment according to FIG. 2 to the normal line state, a signal corresponding to the current I _{3 in FIG. 1b is fed to the control conductor 14.} After this signal has been applied, the operating point b is set , and the gate conductor part 12 A , which consists of soft superconducting material, is in the normal conduction state. If the gate conductor 12 is connected in parallel to another superconducting strip conductor and the current Z ₁ then changes from the gate conductor 12 to the parallel strip conductor, the operating point c is established and the gate circuit remains normally conductive. After this current shift, the signal / _{; J} fed to the control conductor 14 is switched off, and the gate circuit again assumes its superconducting state at the operating point d ; Now-no current flows in the gate ladder 12.

As soon as the current I ₁ . is switched back from the parallel strip conductor to the gate conductor 12, the gate circuit resumes its original state at the operating point α . The in F i g. 1 b by the square of the operating points a, b, c, d operating mode is suitable for a circuit arrangement in which two gate circuits are connected to each other in such a way that the control conductor of one is in series with the gate conductor of the other gate circuit, so that one gate circuit excites the other. In such a case, the control conductor current for one gate circuit is equal to the gate conductor current for the other gate circuit, ie it is Z ₁ = 7. _r The actual gain of such a circuit arrangement is 1, but it is - as shown in FIG. 1 can be seen - possible to switch the gate conductor part 12 A from the superconducting to the normally conducting state in that the value of the supplied signal is smaller than Ι _Ά . In this case, a gain factor greater than 1 is achieved.

It is of course not always necessary to have a gain factor greater than 1 available and other modes of operation can also be used

the gate circuit can be realized. For example, space S between the first gate ladder 12 ^ 4 and the can, as in FIG. 1, a single control lead 14 and control lead 14.4. The other critical distance Γ can be used, which is excited by a signal from sufficient- is located between the first gate conductor 12 A and the size to transfer the gate conductor 12 into its shielding conductor 18. Again, the normal conduction state is to be transferred through this. The gain factor that can be achieved at the control arrangement through conductor 14 is then greater than that determined by the ratio T: S. Gate ladder 12 led electricity. Of course, a part of FIG. 4a is a perspective view showing

this control signal is to be regarded as pre-excitation, as the embodiments according to FIG. 3 will. and 4 can be carried out in practice. Included

If a real amplification is achieved, the upper shielding conductor 16 is still only the result of the use of a de-excitation current in relation to its actual position together with the control signal. raised in order to make the arrangements of the other conductors visible. This is only possible with a gate circuit with a ser. The other distances characteristic curve slope of greater than 1, as shown in the ladder to each other, are not necessarily to scale. Ib is shown. For this purpose, the thickness of the soft 15 must be true, since in such a schematic drawing superconducting gate conductor part 12 A when operating the temperature, the representation of the principle of temperature is primarily greater than the current penetration depth of the.

relevant material. The characteristic curve 215 is in the diagram of FIG. 4b

In Fig. FIG. 3 is a further embodiment of the process for the embodiment according to FIG. 4 shown. The invention represented with an additional second ao is a very interesting property of this Ausfüh-Torleiter26, which is connected and arranged in such a way that this characteristic curve 215 is essentially that it flows the same but opposite - a mirror image of the characteristic curve 21 in the diagram of the current as the first gate conductor 12 conducts. This is in Fig. Ib. In FIG. 4 b, the greatest slope of FIG. 3 is shown by the dot symbol to the left of the characteristic curve 215 by the straight line 225. The second goal ladder 26 indicated. In this variant, the straight line 24 B represents the slope 1. All the rest of the structure of the gate circuit with respect to the details in FIG. 4b are symmetrical with similar book control conductors 14. The two goal posts are designated as the corresponding parts in ladders 12 and 26 at the same distance from the control Fig. Ib. In Fig. 4b, the part of the characteristic curve 215 occurs ladder 14 attached on opposite sides. with maximum gain in the positive quadrant The shielding conductors 16 and 18 are also at the same time, where both the gate ladder and the control distance beyond the gate ladder 26 and 12 flow in a positive direction. This is strange. In this embodiment, this occurs extremely interesting, since in known embodiments, magnetic saturation again between the gate of parallel cryotrons generally assumed conductor 12 and the shielding conductor 18 in the space denoted by 5 that the space corresponding to the greatest amplification occurs. The other critical part of an asymmetrical superconductivity level T is the distance between the gate conductor 12 speed characteristic in the area of the negative control current and the control conductor 14. Since the second gate conductor 26 occurs, as shown in FIG. Abandoned and the first gate conductor 12 carry the same current, but differ from the differences mentioned for the opposing control currents, their respective magnetic and gate conductor currents in the embodiments according to magnetic coupling to the control conductor 14 are the same, 40 FIGS. 3 and 4 are the speed of sound and dispensers of opposite signs. As a result, the strengthening factor in both embodiments does not result in the entire mutual inductive coupling being at risk of the same, of course under the condition of the point where current flows through the control conductor, to the same ratio T: S. The efficiency of zero. In this way, a degenerative in-embodiment according to P i g. 4, however, somewhat negative coupling is largely eliminated. Therefore, because of the closer coupling between the gate circuit according to Fig. 3 has a substantially control conductor 14 ^ 4 and the first gate conductor 12 ^ 4, such as greater switching speed than the embodiment, it basically the structural arrangement of forms according to Fig. 1 and 2 This is therefore the case, Fig. 4 is peculiar to. The reason for this is the requirement that the gate conductor is inductively coupled to the fact that the magnetic saturation space and thus the control conductor no longer counteracts or hinders the generation of a current in the small distance S between the first gate conductor and the latter Control conductor 14 ^ 4 must be. changes. The operating characteristic for switching between- The embodiment of the gate circuit according to

see superconductivity and normal conductivity in FIG. 4 may be varied within the meaning of Torleiterteil 12 A of a gate circuit according to Fig. 3 is again Fig. 5 is the same as g in order to achieve a regenerative gegenim substantially in F i. 1 b shows the inductive coupling between the control curve for the embodiments according to ladder 145 and the gate ladders 125, 265. That is, FIG. 1 and 2. the inductive coupling between the gate ladders and

In Fig. 4 is a further variant of the invention the control conductor is such that the use of the control current, likewise using a second gate conductor, which the gate circuit is shown in its standard, which corresponds to the embodiment according to FIG. 3 60 conduction state switches, is favored, resembles (cf. distinctive reference symbol ^ 4), however this modification to achieve a regenerative with the exception that the distances between the conductors of coupling are achieved by the fact that the one another is now different and the control current in the control conductor 145 from the center of the arrangement control conductor 14 ^ 4 now moved out in the same direction as that, so that it flows to the first gate conductor 125 current in the first gate conductor 12 A. This is closer to 65 than to gate ladder 265. As a result, the drawing is indicated by the plus signs to the left of the coupling from the first gate ladder 125 to the control ladder ladders 12/1 and 14 ^ 4. In this embodiment, enlarged compared to that of the second guide form, the magnetic saturation occurs in the gate conductor 265 to the control conductor 145. In addition, it is

advantageous, also the distance between the second gate conductor 26 B and the shielding conductor 16 in the embodiment according to FIG. 5 to enlarge. As in all other embodiments, the gain factor is also represented here by the ratio T : S , with these letters in FIG. 5, the same critical distances are designated as in the embodiment according to FIG. 4th

F i g. 6 is a variant of the embodiment according to FIG. 5 with a pre- excitation conductor 2OB. As already in connection with the embodiment according to FIG. 2, the pre-excitation conductor actually represents nothing more than an additional control conductor, which offers the advantage of a separate electrical circuit for the pre-excitation signal. Otherwise, the embodiment corresponds to the gate circuit according to FIG. 6 by and large of those according to FIG. 5.

The embodiments of the gate circuits according to FIG. 5 and 6 both have roughly the same supra-ao conductivity characteristics as shown in FIG. 4 b already are shown. A characteristic curve is essential for the principle of a regenerative inductive coupling, at which the maximum gain is reached in the positive current quadrant.

The regenerative inductive coupling is an extraordinary and unexpected result in view to the previous view that mutual inductive coupling was made to a minimum because it has a degenerative influence and always leads to an extension of the switching time lead.

Claims (8)

Claims: 35 1. Kryotrontorschalt, in which consisting of superconducting layers, stacked gate conductor, control conductor and shielding conductor run parallel to each other, wherein a gate conductor with a section consisting of soft superconducting material is provided between a control conductor and a shielding conductor, characterized in that on the of the first-mentioned shielding conductor (18) opposite outer side of the cryotron a second shielding conductor (16) is arranged and that the gate conductor (12, 12 A, 12B) arranged between the control conductor (14, 14 A, 14B) and the first-mentioned shielding conductor (18) is closed one of these conductors has a relatively small distance (S) . 2. Gate circuit according to claim 1, characterized in that the distance between the Control conductor (14) and the shielding conductor (16) adjacent to it is greater than the distance between the gate conductor (12) and the shielding conductor (18) adjacent to it and that an anti-parallel mode of operation of the control conductor (14) and the gate ladder (12) is provided. 3. Gate circuit according to claim 2, characterized in that between the control conductor (14) and the gate conductor (12) a pre-excitation conductor (20) is arranged, the one of the control line current rectified pre-excitation current leads. 4. Gate circuit according to claim 1, characterized in that the control conductor (14) and the gate conductor (12) are provided for an anti-parallel mode of operation, that a further gate conductor (26) is provided between the control conductor (14) and the second shielding conductor (16) whose current is opposite to the current in the first gate conductor (12) is equal, and that the first gate conductor (12) has a smaller distance (S) to the shielding conductor (18) adjacent to it than to the control conductor (14). 5. Gate circuit according to claim 1, characterized in that the gate conductor (12,4,12 B) and the control conductor (14 A, 14B) are provided for a parallel mode of operation that between the control conductor (14 A, 14 B) and the second shielding conductor (16) a further gate conductor (26 ^ 4, 26 B) is provided, the current of which is opposite to the current of the first gate conductor (12A, 12B) and that the distance between the control conductor (14A, 14B) and the first gate ladder (12A, 12B) is smaller than the distance between the first gate ladder and the shielding conductor (18) adjacent to it. 6. Gate circuit according to claim 4 or 5, characterized in that both the two gate conductors (12, 26; 12 A, 26 A) and the two shielding conductors (16,18) to the control conductor (14, 14A) are arranged symmetrically. 7. Gate circuit according to claim 4 or 5, characterized in that the further gate conductor (26, 26/4, 26 B) does not contain a soft superconducting section. 8. Gate circuit according to claim 5, characterized in that between the control conductor (14 B) and the further gate conductor (26 B) close to the control conductor (14 B) a pre-excitation conductor (20 B) is arranged, which carries a current rectified to the control conductor current . Legacy Patents Considered:
German Patent No. 1 162 405. 1 sheet of drawings 809 630/962 10.68 © Bundesdruckerei Berlin